Generally, a conventional image-signal processor (ISP) performs a digital image processing on an image captured by one CCD image sensor.
As shown in FIG. 1, the conventional image-signal processor (ISP) includes first and second image-processing parts. An A/D converter (ADC) converts an analog image signal sent out from the CCD image sensor, into a CYMG image signal. The first image-processing part converts the CYMG image signal into an YCbCr signal. The second image-processing part converts the YCbCr into a YUV signal. Subsequently, an encoder converts the YUV signal into an NTSC/PAL signal for TV display.
In this configuration, the conventional image-signal processor supports only one CCD image sensor. So, two or more cameras, each with the CCD image sensor, are installed to monitor two or more areas simultaneously or one area in a wide range. Images captured by the two or more CCD image sensors have to be digitally processed to be simultaneously displayed on a single monitor. To do this, a video multiplexer is used which receives as many image signals as input from the corresponding cameras, and sends out one image signal as an output, thereby displaying one image consisting of the small-sized captured images on a single monitor.
Generally, the camera includes the CCD image sensor, the A/D converter and the image-signal processor. The image-signal processor includes a timing generation part and an image-signal processing part. An image signal output from the image-signal processor is converted into the NTSC/PAL signal for TV display, thereby displaying the captured image on a monitor. Installation of the cameras to monitor a certain area is on increasing demand. However, the more the area there is to monitor at the same time, the more the camera is required to be installed. This requires additional installation of the image-signal processor in each of the CCD image sensors.